Additional battery capacity

If the battery capacity were simply 20 to 50% more my Focus EV would be the perfect commuter vehicle. I could do more than just going to and from work . . . The occasional side trip would be greatly appreciated. Additionally, simply the nature of traffic in while driving in the Los Angeles area can be quite taxing to the charge. The little bit more would make my life whole bunches better on those days I am required to slog through the slow and go on the 405 freeway just to get somewhere in a timely manner. A range of 120 to miles would far better meet my urban needs.